Attachment of shoe insoles to lasts



June 1, 1965 M.- R. RADCLIFFE ETAL ,186,11

ATTACHMENT OF SHOE INSOLES TO LASTS Filed Aug. 30, 1962 2 Sheets-Sheet l[nuentars Mi/zon i3. Radcliffe Donald L. Bray .By their Afforney J1me1965 M. R. RADCLIFFE ETAL 3,186,113

ATTACHMENT OF SHOE INSOLES TO LASTS 2 Sheets-Sheet 2 Filed Aug. 30, 1962"Mu V I I L United States Patent ATTACHMENT 0F SHOE INSOLES T0 LASTSMilton R. Radcliife, Marblehead, and Donald L. Bray,

Beverly, Mass., assignors to United Shoe Machinery Corporation, Boston,Mass, a corporation of New .Iersey Filed Aug. 30, 1962, Ser. No. 220,3915 Claims. (Cl. 336-43) The present invention relates to improvements inshoemaking operations and more particularly to means and methods forobtaining shoemaking assemblies which include insoles positioned ontothe bottoms of shoe lasts.

Generally, the first step in lasting shoes includes positioning aninsole onto the bottom of a shoe last in order to obtain a shoemakingassembly on which to carry out the remaining lasting steps. To be doneproperly, this positioning should be done both accurately and securely.Otherwise, in practicing the lasting steps which follow such as toelasting, side lasting, etc. and other steps such as edge trimming andthe like, it becomes difiicult if not impossible to obtain a lasted shoewhich is strongly constructed and one in which all of the parts are soaligned, shaped and unified as to contribute to the shoe a clean moldedappearance.

Improper positioning of an insole onto a last bottom which can lead toshoemaking difiiculties usually takes one or both of two forms. Thefirst of these is misplacement which reflects inaccuracy in initiallypositioning the insole onto the last bottom. The second is displacement,which occurs during the lasting steps which follow initial positioning,and, is reflective of insecure positioning of the insole onto the lastbottom.

The lasting steps which immediately following positioning of the insoleonto the last bottom are particularly critical with respect todisplacement. At this point heavy stresses of various kinds are appliedthrough the agency of wipers, clamps, pulling arms and the like, to theshoe assembly, in order to shape, align and unify the various shoe partsinto a shoe whose shape conforms to that of the last or form.

A number of expedients have been proposed for positioning an insole ontoa last bottom. The most common of these is the use of temporary tacks.Others which have been used to a significant extent include the use ofvarious registering means, such as retractable jig pins located in alast bottom which cooperate with complementary jig holes located in aninsole, as well as still others of a similar operating order. These haveall been more or less designed as alternatives for the practice of usingtemporary tacks.

In spite of the shortcomings surrounding the use of temporary tacks;they have to be pulled before removal of the shoe from the last,nevertheless, their use in positioning insoles onto last bottoms isstill next to universal. This has resulted because many of theexpedients proposed as alternatives are expensive in their production,use and maintenance. Many of the others remaining then fail to givepositioning which remains accurate and se curely positioned throughoutthe lasting operation.

It is an object of the present invention to present shoemaking means andmethods for providing shoemaking assemblies in which shoe insoles may beaccurately and securely positioned onto the bottoms of shoe lasts.

It is another object of this invention to provide shoe assemblies asabove which are capable of maintaining accurate and secure positioningbetween insoles and shoe last bottoms throughout the lasting operation.

It is another object of this invention to provide the shoemakingassemblies as above which serve as references from which to last shoeswhich are strongly constructed ,and in which all of the parts are soaligned, shaped and Patented June 1, 1965 unified as to contribute shoeshaving clean molded appearances.

It is another object of this invention to provide shoemaking assemblieswhich can be conveniently disengaged after the lasting operations havebeen carried out to allow for easy removal of the lasted shoes from thelasts.

It is another object of this invention to provide shoemaking assembliesas above which are simple and economical in their production as well asin their use in lasting operations.

These and other objects of the present invention are attained inparticular shoe insoles; in shoemaking assemblies in which theparticular shoe insoles are combined with shoe lasts having cooperatingfeatures; and, in methods of obtaining the shoemaking assemblies. Theshoe insoles of this invention include heel seat portions havingintegrated upwardly projecting registration pins molded from polymericmaterial. In order to coordinate these shoe insoles with shoe lasts insuch a manner as to obtain shoemaking assemblies in which the shoeinsoles are accurately and securely positioned in predeterminedrelationship onto the bottoms of the lasts, the lasts have registrationholes located at the bottoms thereof. The registration pins are locatedon the insoles in correspondingly disposed relationship to theregistration holes located at the bottoms of the lasts. In obtaining theshoemaking assemblies referred to, the registration pins on the shoeinsoles are introduced into the correspondingly disposed registrationholes located at the bottoms of the shoe lasts.

By practice of the present invention, shoe assemblies in which shoeinsoles are accurately and securely positioned onto the bottoms of shoelasts are obtained. The lasting operations which follow on theshoemaking assemblies so obtained are facilitated in ease of operationbecause the probability of the insoles being misplaced or becomingdisplaced during lasting is greatly minimized. The final result of thisis the production of well-constructed shoes. The uppers of shoes soproduced evidence a uniformly clean molded appearance; this includesback parts of the uppers as well, where a clean molded line from topline through the heel is obtained. This is of particular note in thatback parts of shoes represent an area where a great deal of difficultyhas previously been encountered.

The present invention is simple in its practice. Obtaining the necessarycorresponding disposition of registration pins and registration holes inthe insoles and lasts, respectively, can involve use of a master ortemplate in locating both. The registration holes may be provided at thebottoms of the lasts by a simple drilling process. In providing theregistration pins on the shoe insoles, the same master or template isused in making mold parts, for instance, a mold cover which includessecondary mold cavities in which to mold the registration pinssimultaneously and integrally with molding at least the heel seatportions of the insoles.

Because in the shoe assemblies of the invention the bottoms of the lastsare provided with registration holes rather than jig pins, lugs or thelike, no special care is required in handling these lasts during theshoemaking operation. Due to the critical nature of the registrationwhich is necessary for proper positioning, with insoles, lasts havingjig pins very often become crippled, either through damage ormisalignment of the pins, with the rough handling to which lasts areordinarily subjected in shoemaking operations.

Practice of the present invention also leads to eliminating operationalsteps which are ordinarily practiced in removing a lasted shoe, and,similarly disengaging the insole of the lasted shoe from the last, afterlasting. For instance, in practicing this invention there is nonecessity 3 for practicing various tack pulling steps as are necessarywhen temporary tracks are used to position the insoles on the lastbottoms.

The following drawings are included for the purpose of furtherillustrating the invention in which:

FIG. 1 is a diagrammatic view in top perspective showing a shoe insolehaving a heel portion and an integrated pair of registration pins eachmolded from a synthetic polymeric material;

FIG. 2 is a diagrammatic view in bottom perspective showing a shoe lasthaving a pair of registration holes located in the heel plate;

FIG. 3 is a diagrammatic view in side elevation with parts broken awayshowing a shoemaking assembly in inverted position constituted of a shoeinsole positioned on a shoe last; and

FIG. 4 is a diagrammatic view in side elevation with parts broken awayshowing a shoe and last again in inverted position and after the lastingoperation has been completed with the back part of the last disengagedfrom the heel seat portion of the insole of the shoe.

In the drawings, a single embodiment of the present invention is shownby way of illustration. This will now be described. An insole 10 asshown in FIG. 1 may constitute a forepart 12, arch section 14 and a heelseat portion 16. Heel seat portion 16 is molded to shape from apolymeric material such as a foamable thermosetting polyurethane.Forepart 12 and arch section 14 are a single shape, die cut from a sheetof composition material and attached to or unitized with heel seatportion 16 with molding of the latter. The entire insole 10 may bemolded to shape from synthetic polymeric material if desired. It is alsopossible, in a manner not shown, to include a shank piece into a moldedarc section 14 during molding.

A pair of integrally molded registration pins 18 and 20 are shownprojecting upwardly from the top or upper side of heel seat portion 16.By integrally molded is meant that registration pins 18 and 20 areintegrated with heel seat portion 16 by or during molding of the latter,and that a polymeric material is used as the molding material.

Registration pins 18 and 20 as shown are two in number, however, thenumber can range from a single pin which is profiled to contributeaccurate and stably secure positioning both longitudinally and laterallyof the last, to a number of registration pins accomplishing the sameend. Actually two registration pins as shown, perform this purposesuitably while allowing for each pin to have a simple yet convenientlyobtainable cross section, for example, circular, which admits to closemolding, fitting and assembly tolerances. Registration pins 13 and 20which are two in number and which have diameters and projections orheights both as small as inch, have been found to give accurate andsecure positioning of the type desired. Variations from thesemeasurements can also be practiced if desired.

It is recommended that a registration pin, when one is used, orregistration pins when more than one is used, be located consistently inlongitudinal and lateral alignment in relation to the center line of theinsole. This serves to equalize stresses applied to the registrationpins during lasting. In a preferred embodiment each of registration pins18 and 20 is tapered at its projecting end to facilitate its assembly,and later, disengagement from the last. In addition, for convenience indisengaging insoles from the last after lasting, registration pins 18and are both located in the heel seat portion 16 of insole 10. However,it is possible, but not necessary, to position at least some oradditional registration pins at other locations on the insole.

Registration pins 18 and 20 are located on the top surface of insole 10in correspondingly disposed relationship to registration holes 22 and 24located at the bottom of a shoe last 26 as shown in FIG. 2. Morespecifically, the registration holes are shown entering the bottom oflast 26 through heel plate 28 which is secured by a number of screws 30to the bottom of the heel part 32 of last 26. Heel part 32 of last 26 isheld in limited pivotable relationship to forepart 34 by means of ahinge link, not shown, which is fastened in the interior of the last 26by means of pins 36 and 38.

Insole 10 is positioned securely and accurately onto last 26 to obtainthe shoemaking assembly shown in FIG. 3. This calls for introducingregistration pins 18 and 20 of insole 10 into registration holes 22 and24 respectively of last 26. Positioning of the desired type is furtherfacilitated if the top surface of insole 10, particularly at the heelseat portion 16, is contoured in a concave manner complementing thebottom surface of last 26.

After positioning insole 10 onto last 26 in the manner described, thevarious lasting operations such as pulling over, heel lasting, toelasting and side lasting, also the operations of edge trimming, solingand heeling may be carried out with positional reference to both last 26and insole 14 to obtain a lasted shoe 40 as shown in FIG. 4.

On removing shoe 40 from last 26, last 26 is broken at the hinge causingback part 32 to pivot downwardly, as shown, and away from insole 10.This causes registration pins 18 and 20 to become disengaged fromregistration holes 22 and 24 respectively to where they will notinterfere with removal of shoe 40 from last 26, by simple slip or slideaction. Following removal of shoe 40 from last 26, the projecting partsof registration pins 13 and 20 can be effectively eliminated by any oneof a number of convenient methods such as cutting or abrading the pinsdown to flush with the upper surface of insole 10. As a result there areno holes to be filled in nor tacks to be removed from the insole as isquite often the case using the positioning expedients presently known.

The insoles of the present invention have at least their heel seatportions as well as the integrated registration pins molded from apolymeric material which in molded form has sufficient strength towithstand the heavy stresses to which these parts are subjected withlasting. In addition, in molded form the polymeric material shouldexhibit those strength properties which are desirably present duringother shoemaking operations as well as those properties which contributeto desirable shoe wearing. During lasting, stresses of 2000 pounds andgreater are commonly applied to shoe assemblies by action of the wipers,etc. This is for the purpose of pulling various shoe parts into shapedconformation with the last. Under these stresses the registration pinsand similarly the material from which they are molded should not deformas to allow the insole to become significantly displaced or misalignedwith relation to the last. If this occurs a poorly constructed shoe isthe result. It is recommended that the registration pins and insoles bemolded from polyurethanes, polyepoxides and polyesters and similarmaterials in order to obtain this performance. Other polymeric materialswhich may be used include high impact polystyrenes, which have butadieneand/or acrylonitrile in polymerized form either copolymerized or blendedwith polystyrene; also olefinic polymers and copolymers such as those ofethylene and propylene which can be adapted to perform as indicated.Combination of the various polymeric materials can be used.

The registration pins and heel part of the insole may be molded entirelyof polymeric material. However it is more probable to include variousfillers, colorants and the like. It is also possible to utilize thepolymeric material in such a manner as to have the molded insole takethe identity of a laminate, with the polymeric material acting as abinder. Other similar variations can be practiced in molding the insoleand integrated registration pins from the polymeric material.

The polymeric materials preferred for use in providing the insoles ofthe present invention are the polyurethanes. Polyurethanes, asdifferentiated from most synthetic polymeric materials and particularlythermoplastic addition type polymeric materials are easily compounded asnot to creep significantly or lose their dimensions when subjected tostresses of the magnitude encountered in shoe lasting. Simultaneouslythey are not so brittle as to snap .Off under these stresses. Inaddition to that it is desirable that the polymeric material from whichthe heel seat is made be such that it be resistant to splitting whennailed, and, have nail holding ability. This allows heels to be nailedto the shoes. Due to this, polyurethane foam and preferably those havingdensities of to 50 lbs/ft. are recommended with those having a foamdensity range of 25 to 40 lbs ./ft. being particularly recommended.Under conditions of wear, the insoles desirably have the capacity toflex while at the same time being tough, strong and have some resiliencyin order to contribute comfort to the wearer. This too is satisfied bythe use of semi-rigid polyurethane foams in the heel portions ofinsoles. Again, the thermosetting polyurethane foams are also desirablebecause of their relatively light weight, adding to shoe wearingcomfort.

The use of polyurethanes as molding compounds also has the advantagethat it allows registration pins which are of small diameter and few innumber to be used. Neither is it necessary to mold the registration pinsaround dowels or other strengthening members as may be necessary whenthe registration pins are molded from many thermoplastic addition typesynthetic polymers and similar materials. The use of dowels, etc. isextremely difficult to accomplish satisfactorily from the standpoint ofpositioning and in addition it adds difficulty and expense to the stepof removing the registration pins from the insole which is carried outafter lasting. Polyurethane materials are readily available, and variouscompositions and processes are used in their production and use. Thefollowing indicates one manner of producing a semirigid foamedpolyurethane which is etfective for molding the insoles of the presentinvention. An excess of polyisocyanate, such as toluene diisocyanate, isreacted with an organic compound having at least two reactive hydrogengroups, for instance castor oil, to provide a polyester urethane havingterminal isocyanate groups. This is an intermediate product which iscommonly referred to as a prepolymer. A polyol such as a pentol obtainedfrom reacting propylene oxide with diethylene triamine, a catalyst, suchas dibutyl tin dilaurate, and water are mixed with the prepolymer toreact further to a final semi-rigid molded foam. The water reacts withthe terminal isocyanate groups of the prepolymer to bring aboutcrosslinking and production of carbon dioxide. Cross linking bringsabout solidification of the reacting mass, while the carbon dioxideserves to act as an expanding agent in the reacting mass.

The mixture of prepolymer, polyol, catalyst and water is charged into amold having a mold cavity, complementing at least the heel seat portionof the insole and secondary cavities complementing the registrationpins. The cross-linking reaction is allowed to take place there toobtain an insole having a molded heel seat portion and integral moldedregistration pins of semi-rigid polyure thane foam. The molds andmolding processes which may be used are described with more detail in mycopending application Serial No. 220,505, filed of even date.

The following example is included for the purpose of further describingthe invention. Where parts are menti-oned parts by weight are intendedunless otherwise described.

Example I (A) Molding charge preparation-A prepolymer is prepared byreacting 900 parts of castor oil with 525 parts of toluene diisocyanate.The reaction is carried out by heating the mass at 80 C. for a period of120 minutes.

A reactant addition is made up by mixing 130 parts of a pentol, which isa condensation product of diethylene triamine and propylene oxide, withparts of castor oil, 2 parts of tetramethyl butane diamine (catalyst), 1part of dibutyl tin dilaurate (catalyst) and 1 part of water.

(B) Mold preparationz-The heel bottoms of a pair of plastic(ethylene-butene copolymer) lasts for ladies shoes are provided withpairs of holes inch in depth and diameter, spaced 1 /2 inches inlongitudinal alignment on the center line of the last bottom. Acontoured steel template is used for locating the holes. A pair of moldbodies are made from the plaster of Paris using the bottoms of the laststo which insoles are attached for shaping the mold cavities. Apolyethylene mold cavity liner which complements the shape of the entirebottom of the plastic lasts is then inserted in the mold cavities.

(C) Insole m0lding.An insole piece including a forepart and arch portiondie cut as a single unit from latex bonded cardboard (0.060 inch thick),is positioned in the forward part of each ofthe lined molding cavities.A molding charge constituting 2 parts of prepolymer and 1 part ofreactant addition, having a total weight of about 20 grams and in fluidform is then charged into each cavity, and the corresponding drilledplastic lasts matching in size those used to make the mold cavity areclamped in partially inserted position into the cavities. An exothermicreaction takes place in each case converting the fluid polyurethanecharge to a semi-rigid polyurethane foam having a density of about 35pounds per cubic foot. Time for reaction is about 15 minutes.

When the molds are opened insoles having pairs of registration pinscorresponding to the holes in the bottom of the plastic lasts can beeasily removed. The back parts of each of the insole, which are ofsemi-rigid foam, are strongly adhered to the inserted insole pieces.

(D) Lasting 0perati0n.-The same plastic lasts which are used in moldingthe insoles can be used to last a pair of shoes. The insoles arepositioned on the lasts by inserting the registration pins of the insoleinto the registration holes located in the last bottoms. The shoemakingassemblies so obtained are each placed in a combined back part moldingand heel seat lasting machine together with a corresponding prestitchedupper. There the upper is shaped to fit the back part of the last by thewiping action of the pair of wipers exerting about 200 pounds perperipheral inch of heel seat wiped. Attachment of the upper to theinsole is obtained through a ribbon of adhesive applied to the peripheryof the heel seat portion of the insole. The partly lasted shoe is placedin a side laster, and later a toe laster, the toe laster again using apair of wiper arms, where the remaining lasting steps are carried out.Thereafter an outsole is cemented on and a heel is nailed onto each ofthe shoes. Following that edge trimming and finishing of the shoes arecarried out.

After finishing, the last is broken at the hinge and the shoes slippedoff the last. The registration pins which have remained intactthroughout the lasting operation are snipped off flush with the insoleupper surface using blunt nosed snippers, and, a sock lining is cementedonto the insole.

When the shoes so obtained are examined, their back parts exhibit aclean molded appearance from top line through heel. All the parts of theshoes are extremely well aligned, not only with respect to one anotherbut as to reproduction between shoes. When the shoes are worn it isnoted that they hold up exceptionally well and are comfortable. Bothproperties can be attributed to the excellent alignment of the variousparts of the shoes, and the high fidelity which the shoes show with theshape of the last, and, correspondingly the shape of the foot which thelast is designed to reproduce.

It will thus be seen that the objects set forth above among those madeapparent from the preceding description and efficiently attained, andsince certain changes may be made in carrying out the above process, inthe described insoles, shoemaking assemblies, and shoemaking methods setforth without departing from the scope of the invention it is intendedthat allrnatter contained in the above description and the accompanyingdrawing shall be interpreted as illustrative and not in a limitingsense.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

1. Shoe insoles adapted to be accurately and securely positioned inpredetermined relationship onto the bolttoms of shoe lasts havingregistration holes located at the bottoms thereof, the said insoleshaving at least the heel seat portions thereof formed of syntheticpolymeric material and having integrally formed therewith registrationpins projecting upwardly from the top surface thereof, the saidregistration pins being located on the top surface of the insole to bein correspondingly disposed relationship to the registration holeslocated at the bolttoms of the shoe lasts.

2. Shoe insoles according to claim 1 wherein the registration pins aretwo in number.

3. Shoe insoles according to claim 2 wherein the regis- 8 tration pinsare located in longitudinal alignment relative to the center line of theinsole.

4. Shoe insoles according to claim 2 wherein the registration pins arelocated in the heel seat portion of the insoles.

5. Shoe insoles according to claim 1 wherein the insole and theregistration pins are molded polyurethane foam.

References Cited by the Examiner UNITED STATES PATENTS 456,677 7/91McIntyre 3643 X 645,038 3/00 Lyons 12129.6 1,470,651 10/23 Stewartl2-l29.6 1,736,276 11/29 Pym 12129.6 1,899,057 2/33 Pym 12129.62,340,582 2/44 Cushman 12129.6

FOREIGN PATENTS 574,429 1/46 Great Britain.

JORDAN FRANKLIN, Primary Examiner.

FRANK J. COHEN, Examiner.

1. SHOE INSOLES ADAPTED TO BE ACCURATELY AND SECURELY POSITIONED INPREDETERMINED RELATIONSHIP ONTO THE BOTTOMS OF SHOES LASTS HAVINGREGISTRATION HOLES LOCATED AT THE BOTTOMS THEREOF, THE SAID INSOLESHAVING AT LEAST THE HEEL SEAT PORTIONS THEREOF FORMED OF SYNTHETICPOLYMERIC MATERIAL AND HAVING INTEGRALLY FORMED THEREWITH REGISTRATIONPINS PROJECTING UPWARDLY FROM THE TOP SURFACE THEREOF, THE SAIDREGISTRATION PINS BEING LOCATED ON THE TOP SURFACE OF THE INSOLE TO BEIN CORRESPONDINGLY DISPOSED